The simplest of the tops I make is the gathered one you’ve seen in most of the swimsuit tutorial posts so far. It is made from two straps, a rectangle for the front, a matching rectangle of lining fabric, and optional molded cups. The first step, of course, is making a pattern. For this swimsuit the pattern is so simple I won’t give you anything to print out. Just take a ruler and start measuring.
You only need one measurement to make this swimsuit: the distance between your arm pits, measured over your breasts. Subtract 2-4″ inches from this, depending on your size and how tightly you want the swimsuit to fit, and you have the length of your front piece. Measure out this length along the edge of your fabric. Measure up 5-7 inches, depending on your size and how much coverage you want. Cut out a rectangle with these dimensions (2-4″ less than your armpit to armpit measurement X 5-7″).
For the lining, cut a bow tie shape that is as long as your rectangle and has the same height sides, but dips in at the center. If you don’t have lining material, cut this out of your main fabric
For the straps, cut two strips of fabric 3″ wide and as long as your fabric (45″-60″). You can taper the ends if you want, or leave them square. Place two marks 5-7″ apart (the width of your center piece) near the middle of each strip. This is where you will sew in the front of the swimsuit.
The first step in sewing up your swimsuit is to gather the center front. Using a long stitch length, sew a line down the center of the rectangle. Tie together the two threads at one end. At the other end, pull on one thread and push back the fabric so it gathers. When the gathered center is the same length as the center of the lining, tie together the two threads on this side. Sew over your gathers a couple of times to reinforce them.
I strongly recommend you sew in some sort of padding. They give the swimsuit a bit of structure and hold the edges right where you want them. You can do this with elastic instead, but reinforcing the fabric with pads makes for a much more comfortable swimsuit. Removable pads don’t really do this. They have a terrible habit of trying to remove themselves while you’re swimming, and you don’t really want to be standing on the beach rearranging them. Make sure you’re using something that can go through the washing machine and dryer of course, but anything that goes in a swimming pool should be washable. I cut out an appropriate shape from a sheet of bra-making fabric, but if you’re only making one suit it makes a lot more sense to buy molded cups.
If I’ve convinced you that you need to sew in molded cups, this will be the next step in making your swimsuit top. Sew the cups to the lining using an 1/8 inch zig zag.
Next, pin the lining to the front with the right sides facing in (for the lining, the cups are sewn to the wrong side). Sew along the top and bottom (the long sides) and turn right side out.
Fold the straps in half lengthwise with the right sides facing in. Sew up each end of each strap up to the marks you made using a slight zig zag stitch. Turn right side out.
Sew the front of the bikini to the straps between the marks. To make this look tidy, sew the back of the strap down first, then fold over the front and carefully top stitch. If that doesn’t make any sense, just sew them together. It will look good on, and that’s all that really matters.
Next: other bikini top styles.